const promise = new Promise((resolve, reject) => {
  const error = false;
  if (!error) {
  resolve({ name: "John", age: 30 });
  } else {
  reject("出现了问题");
  }
  });
  promise
  .then(user => {
  console.log(user);
  return user.name;
  })
  .then(name => {
  console.log(name);
  return name.length;
  })
  .then(nameLength => {
  console.log(nameLength);
  })
  .catch(error => {
  console.log(error);
  return 123;
  });

